Antimicrobial Activity Of Essential Oil Emulsions And Possible Synergistic Effect On Food Borne Pathogens

The objective of this study was to evaluate the antimicrobial activity of essential oil emulsions against food borne pathogenic bacteria and determine potential applications. The oils used for this study were cinnamon, oregano, clove, thyme, rosemary, sage, bergamot, nutmeg, lemon grass and bay. Oil in water emulsions were prepared using Tween 80 as an emulsifying agent, with a stock oil concentration in the emulsions of 20,000 ppm. Essential oil emulsions were individually screened against E. coli (ATCC 25922), E. coli (ATCC 700927), L. monocytogens (ATCC 19115), L. innocua (ATCC 33090) and S. Typhimurium (ATCC 19585) using the broth micro dilution method. Cinnamon showed the highest antimicrobial efficacy against all test organisms, as determined by the minimum inhibitory concentration (MIC). Oregano had the second highest efficacy, while the other oils did not exhibit high antimicrobial activities. To determine synergistic effect of the emulsions, combinations were tested using checkerboard method. The only synergism observed was between cinnamon and oregano against E. coli (ATCC 700927) and L. innocua (ATCC 33090) and also between cinnamon and clove towards L. innocua (ATCC 33090). All other combinations were additive or indifferent in nature to the test organisms. To determine antimicrobial activity of the essential oils on food, chicken pieces were inoculated with the bacteria standardized in CAMHB, and consequently treated with a twofold concentration of the individual in vitro MIC of the EOs that expressed synergism. The pieces were placed in 60 mm dishes and stored under refrigeration at 4ºC. Samples were prepared for day 0, day 1, day 3 and day 6 for each bacterial treatment.Cinnamon in comparison to control showed Log reduction of E. coli (ATCC 25922), E. coli (ATCC 700927), L. monocytogens (ATCC 19115), L. innocua (ATCC 33090) and S. Typhimurium (ATCC 19585) by 2.885, 3.39, 3.275, 4.29 and 3.06. While oregano reduced E. coli (ATCC 25922) and E. coli (ATCC 700927) by 3.21 and 3.53 Log. All bacterial species showed significant reduction (p \u3c 0.05) in comparison to control samples. These results suggest that essential oil emulsions have the potential to be used as antimicrobial agents for enhancing food safety

Haematological profile of dengue fever

Background: Dengue is a viral illness that is increasingly becoming endemic in India. This study aimed to study the haematological profile of patients diagnosed with dengue infection in a tertiary care hospital.Methods: 89 patients suspected of having dengue illness were followed. Out of which those confirmed by positive serology were followed and studied in detail (n=46).Results: Common clinical symptoms were fever, vomiting, and abdominal pain. Common haematological abnormalities were thrombocytopenia and leucopoenia. All patients improved clinically with improvement of biochemical and hematological parameters. None of the patients died in this series.Conclusions: Dengue Fever continues to be a significant health problem especially in Northern region of India. A sharp vigilance is required by concerned authorities to prevent and minimize any future outbreak. It is extremely important to implement and maintain an effective, sustainable and community based disease prevention program

Kala-azar without splenomegaly: A rare presentation

Visceral leishmaniasis is a major public health problem in Bangladesh, North East India, Nepal, Sudan and North East Brazil. In India, leishmaniasis is more prevalent in Bihar, Jharkhand, West Bengal and Uttar Pradesh. We present the case of a 55-year-old male farmer from Himachal Pradesh with complaints of fever for 2.5 months, appetite loss and weight loss for 1 month. On evaluation, he was found to have pancytopenia, transaminitis, and hyperbilirubinemia. Tropical fever serology and viral markers were negative. Blood and urine cultures were sterile, and ascitic fluid was acellular and high SAAG with normal ADA. Bone marrow was done due to non-responding pancytopenia which reveals intracellular amastigote form of Leishmania Donovani. A final diagnosis of Kala-azar without splenomegaly with moderate ascites was made as an absence of splenomegaly was the most striking aspect in our patient

Effect of prophylactic tranexamic acid in normal vaginal delivery

Background: Use of tranexamic acid (TXA) in combination with uterotonics in management of postpartum haemorrhage is quite established, but its use for prophylaxis is still uncommon, specifically post normal delivery. Shock index (SI) (heart rate divided by systolic blood pressure) and delta shock index (DSI) i.e., difference of SI before and after an event are being recognized as tools for hemodynamic status evaluation and bedside assessment for individual respectively. The present study compared the combined effect of TXA and oxytocin uterotonic on postpartum blood loss as evaluated by shock index (SI) and delta shock index (DSI) in low-risk pregnancies.Methods: 230 subjects divided equally, underwent randomised control trial with combination of Injection TXA and oxytocin versus oxytocin alone immediately post-delivery and impact evaluated using SI, DSI, postpartum haemoglobin (HB) and haematocrit (HCT) at admission and one hour postpartum, followed for six weeks for any complications.Results: Prophylactic use of TXA in terms of SI values, HB and HCT revealed significant improvement, in both preterm and term pregnancies with either spontaneous or induced labours. DSI with a sensitivity of 69.6% and specificity of 67% with a simple plus or minus notation gave a satisfactory idea of shift of stability and instability of hemodynamic status of an individual as an indirect predictor of blood loss with a cut-off between -0.0682 to +0.1182. 6 weeks postpartum follow up was uneventful.Conclusions: The study depicted benefit and safety profile of prophylactic use of TXA in low-risk pregnancies, significant for developing countries with high incidence of anaemia during pregnancy and advocates incorporation of SI and DSI as markers of haemodynamic status in partograph

Crystal structures of the Streptomyces coelicolor TetR-like protein ActR alone and in complex with actinorhodin or the actinorhodin biosynthetic precursor (S)-DNPA.

Actinorhodin, an antibiotic produced by Streptomyces coelicolor, is exported from the cell by the ActA efflux pump. actA is divergently transcribed from actR, which encodes a TetR-like transcriptional repressor. We showed previously that ActR represses transcription by binding to an operator from the actA/actR intergenic region. Importantly, actinorhodin itself or various actinorhodin biosynthetic intermediates can cause ActR to dissociate from its operator, leading to derepression. This suggests that ActR may mediate timely self-resistance to an endogenously produced antibiotic by responding to one of its biosynthetic precursors. Here, we report the structural basis for this precursor-mediated derepression with crystal structures of homodimeric ActR by itself and in complex with either actinorhodin or the actinorhodin biosynthetic intermediate (S)-DNPA [4-dihydro-9-hydroxy-1-methyl-10-oxo-3-H-naphtho-[2,3-c]-pyran-3-(S)-acetic acid]. The ligand-binding tunnel in each ActR monomer has a striking hydrophilic/hydrophobic/hydrophilic arrangement of surface residues that accommodate either one hexacyclic actinorhodin molecule or two back-to-back tricyclic (S)-DNPA molecules. Moreover, our work also reveals the strongest structural evidence to date that TetR-mediated antibiotic resistance may have been acquired from an antibiotic-producer organism

Genomic and Metabolomic Analysis of the Potato Common Scab Pathogen Streptomyces scabiei

Streptomyces scabiei is a key causative agent of common scab disease, which causes significant economic losses to potato growers worldwide. This organism produces several phytotoxins that are known or suspected to contribute to host–pathogen interactions and disease development; however, the full metabolic potential of S. scabiei has not been previously investigated. In this study, we used a combined metabolomic and genomic approach to investigate the metabolites that are produced by S. scabiei. The genome sequence was analyzed using antiSMASH and DeepBGC to identify specialized metabolite biosynthetic gene clusters. Using untargeted liquid chromatography-coupled tandem mass spectrometry (LC-MS2), the metabolic profile of S. scabiei was compared after cultivation on three different growth media. MS2 data were analyzed using Feature-Based Molecular Networking and hierarchical clustering in BioDendro. Metabolites were annotated by performing a Global Natural Products Social Molecular Networking (GNPS) spectral library search or using Network Annotation Propagation, SIRIUS, MetWork, or Competitive Fragmentation Modeling for Metabolite Identification. Using this approach, we were able to putatively identify new analogues of known metabolites as well as molecules that were not previously known to be produced by S. scabiei. To our knowledge, this study represents the first global analysis of specialized metabolites that are produced by this important plant pathogen

Identification of a conserved N-terminal domain in the first module of ACV synthetases

Abstract The l‐δ‐(α‐aminoadipoyl)‐l‐cysteinyl‐d‐valine synthetase (ACVS) is a trimodular nonribosomal peptide synthetase (NRPS) that provides the peptide precursor for the synthesis of β‐lactams. The enzyme has been extensively characterized in terms of tripeptide formation and substrate specificity. The first module is highly specific and is the only NRPS unit known to recruit and activate the substrate l‐α‐aminoadipic acid, which is coupled to the α‐amino group of l‐cysteine through an unusual peptide bond, involving its δ‐carboxyl group. Here we carried out an in‐depth investigation on the architecture of the first module of the ACVS enzymes from the fungus Penicillium rubens and the bacterium Nocardia lactamdurans. Bioinformatic analyses revealed the presence of a previously unidentified domain at the N‐terminus which is structurally related to condensation domains, but smaller in size. Deletion variants of both enzymes were generated to investigate the potential impact on penicillin biosynthesis in vivo and in vitro. The data indicate that the N‐terminal domain is important for catalysis

Specialized Metabolites from Ribosome Engineered Strains of Streptomyces clavuligerus

Bacterial specialized metabolites are of immense importance because of their medicinal, industrial, and agricultural applications. Streptomyces clavuligerus is a known producer of such compounds; however, much of its metabolic potential remains unknown, as many associated biosynthetic gene clusters are silent or expressed at low levels. The overexpression of ribosome recycling factor (frr) and ribosome engineering (induced rpsL mutations) in other Streptomyces spp. has been reported to increase the production of known specialized metabolites. Therefore, we used an overexpression strategy in combination with untargeted metabolomics, molecular networking, and in silico analysis to annotate 28 metabolites in the current study, which have not been reported previously in S. clavuligerus. Many of the newly described metabolites are commonly found in plants, further alluding to the ability of S. clavuligerus to produce such compounds under specific conditions. In addition, the manipulation of frr and rpsL led to different metabolite production profiles in most cases. Known and putative gene clusters associated with the production of the observed compounds are also discussed. This work suggests that the combination of traditional strain engineering and recently developed metabolomics technologies together can provide rapid and cost-effective strategies to further speed up the discovery of novel natural products

Tetrahydropyrazolo[1,5-a]Pyrimidine-3-Carboxamide and N-Benzyl-6′,7′-Dihydrospiro[Piperidine-4,4′-Thieno[3,2-c]Pyran] analogues with bactericidal efficacy against Mycobacterium tuberculosis targeting MmpL3

Mycobacterium tuberculosis is a major human pathogen and the causative agent for the pulmonary disease, tuberculosis (TB). Current treatment programs to combat TB are under threat due to the emergence of multi-drug and extensively-drug resistant TB. As part of our efforts towards the discovery of new anti-tubercular leads, a number of potent tetrahydropyrazolo[1,5-a]pyrimidine-3-ca​rboxamide(THPP) and N-benzyl-6′,7′-dihydrospiro[piperidine-4,​4′-thieno[3,2-c]pyran](Spiro) analogues were recently identified against Mycobacterium tuberculosis and Mycobacterium bovis BCG through a high-throughput whole-cell screening campaign. Herein, we describe the attractive in vitro and in vivo anti-tubercular profiles of both lead series. The generation of M. tuberculosis spontaneous mutants and subsequent whole genome sequencing of several resistant mutants identified single mutations in the essential mmpL3 gene. This ‘genetic phenotype’ was further confirmed by a ‘chemical phenotype’, whereby M. bovis BCG treated with both the THPP and Spiro series resulted in the accumulation of trehalose monomycolate. In vivo efficacy evaluation of two optimized THPP and Spiro leads showed how the compounds were able to reduce >2 logs bacterial cfu counts in the lungs of infected mice